Why can’t I access my Cisco firewall through a web browser? (Part II)

In part one of this series we explored possible configuration errors that could prevent you from connecting to your Cisco Firewall via a web browser. This involved checking the HTTP commands from the Cisco CLI. In the second part of this series we will look at other possibilities that could be preventing you from making this connection.

Two other possibilities are that the ASDM image is either not referenced in the firewall configuration, or, the ASDM image is missing entirely. To check on the first possibility execute the following command from the Cisco CLI.

SHOW RUN ASDM

This command should return something similar to the following:

ASDM IMAGE DISK0:/asdm.bin

This line instructs the firewall of the location of the ASDM image file. If this syntax does not exist it could be that your firewall is missing an ASDM image altogether. Let’s check to see what is on flash.

SHOW DISK0:

This will return everything that is currently on your flash drive. An ASDM image will be a BIN file but potentially it could be named anything on the flash. By default when you download these files from Cisco they are named asdm-<version>.bin. So if you see anything like this then your image file is present, just unlinked.

If this is the case you can set your image file with the following command.

ASDM IMAGE DISK0:/<filename>

Substitute <filename> for the name of the ASDM bin image. Confirm your settings with a quick SHOW RUN ASDM.

Remember to save your changes with a WRITE MEMORY.

Then try to access ASDM again through your web browser.

In part 3 of this series we will look at the possibility that your flash doesn’t have an ASDM image and what to do about it.